Suseción Fibonacci con la Shell Bash.

fibo.sh

# Fibo between 0 and 30.
len=30
arr=()

for (( i = 0; i < len; i++ )); do
  if (( i > 0 )); then
    let arr[i]="arr[i - 1] + arr[i - 2]"
  else
    let arr[i]=i
  fi
  echo ${arr[i]}
done